1. Field of the Invention
The present invention relates to wireless local area network (WLAN) devices and in particular to implementing location awareness in such WLAN devices.
2. Description of the Related Art
Wireless local area networks (WLANs) are becoming increasingly popular as communication networks in many countries. Different countries can have different channel restrictions and/or power requirements for WLAN operation. To receive a certification from a country's spectrum regulator, e.g. the FCC in the U.S., a manufacturer must ensure that its WLAN devices can be configured to operate in the correct channel and power setting for that country. Allowing certification of frequency-selectable WLAN devices, thereby allowing a WLAN device to be configured for operation in multiple countries, would reduce production, testing, distribution, and stocking costs. This lower manufacturer cost should increase competition, and, ultimately, lower prices of the WLAN devices, thereby benefiting consumers.
Unfortunately, configuring a frequency-selectable WLAN device may be too tedious, time consuming, and/or challenging for end users to perform, thereby potentially resulting in the WLAN device operating on an illegal channel or at an illegal power level. To solve this problem, some access points provide a configuration software/menu that allows the end user to simply choose the country of operation. However, end users wishing to enable operation across a larger number of channels than legally allowed may opt to use an alternate country setting in the access point that will enable operation in additional channels at higher, but illegal, transmit power levels. Additionally, illegally imported access points may operate on channels that are illegal in the country of operation.
To further complicate WLAN operation enforcement, current IEEE standards, e.g. 802.11d and 802.11h, allow a WLAN client to be automatically configured by a country setting transmitted by its associated WLAN access point. Thus, if an access point is not configured to transmit the correct country information (whether intentionally or unintentionally), then not only the access point but also its associated clients may operate on channels illegal in the country of operation.
One solution for meeting the requirements of a spectrum regulator is to permanently configure an access point to conform to that country's channel and power settings. However, from a vendor's perspective, more “stock kit units” (SKUs), i.e. different versions of a product, are typically undesirable.
Another solution for meeting the requirements of a spectrum regulator is to implement additional radio hardware/software, e.g. a GPS receiver, to incorporate geo-location capability in the access point. With advancements in GPS signal processing techniques and reduced hardware costs, implementing a low-cost, specialized GPS feature in WLAN access points is now feasible. Although GPS signals are transmitted at different frequencies than WLAN devices, an access point could implement a separate, specialized, receive antenna for the GPS signals, thereby enabling an improved solution. GPS signals may not be received reliably indoors, which is where an access point is typically located.
Notably, as described below in accordance with the present invention, advancements in GPS technology specially adapted for a fixed location awareness application in access points may now be feasible when implemented using algorithms that can take advantage of access point startup routines and occasional recheck periods without hindering normal access point operation. Specifically, an improved solution for implementing location awareness in WLAN devices can be implemented by taking advantage of an ambient country identifier (ACI) technique in combination with new GPS capability in the same access point.